In a supermarket and the like, commodities affixed with code symbols such as barcodes and two-dimensional codes (e.g., QR codes (registered trademark)) are sold. The code symbols of the commodities are obtained by non-intrinsically and latently symbolizing, on the basis of a fixed rule, codes for specifying the commodities. The code symbols are optically read and decoded by a code reading apparatus such as a barcode scanner.
Some code reading apparatus picks up an image of a commodity or the like with a digital camera such as a CCD (Charge Coupled Device) image sensor, detects a code symbol from the picked-up image, and decodes the code symbol. A store clerk takes out a commodity stored in a shopping basket carried onto a counter table by a customer and holds the commodity over the digital camera of the code reading apparatus to input and register a code of the commodity to be purchased by the customer.
In the code reading apparatus in the past explained above, at an interval after reading of a code from a picked-up image, the next code is read. In this way, a code by the same code symbol is prevented from being read twice. However, in the code reading apparatus in the past, a code is read twice if a code symbol stays long in a reading area of the digital camera when the store clerk holds a commodity over the digital camera or if a commodity that frames out of the reading area of the digital camera enters the reading area again. Therefore, the code reading apparatus is insufficient to prevent a code from being read twice.